In spite of the progress made against cancer, it is still the second-leading cause of death in America after cardiovascular diseases. One of the major hurdles in the battle against cancer is that chemotherapy agent selections for any individual patient are not truly personalized. While “cancers” share many characteristics in common, each particular cancer has its own specific characteristics. Genetics and environmental factors have a complex interplay in severity and prognosis of treatment.
It has been recognized that when patient cells are removed from their in situ locations in tissues and cultured in vitro, the cells are subject to phenotypic and genotypic drift, i.e., they begin to lose some of the morphological features (and components) of some characteristic of their tissue or organ of origin, sometimes as a result of changes in expression of a gene, or expression of mutated gene. As a result, simply excising cells from normal and tumor tissues and culturing them in vitro is not satisfactory, since adaptation to culture conditions causes repression of components that are expressed in tumor tissue or in normal tissue and may also cause expression of components that are not normally present in tumor or normal tissue.
Currently, chemotherapy choices are based primarily on a combination of the average population response, as published in peer reviewed journal articles, and the treating physician's professional experience. In treating cancer patients with highly toxic chemotherapy, oncologists are faced with the challenge of selecting a therapy regimen for a particular patient with prospective indicators as to what drug might actually work best for that specific patient.
Culture condition variations, selective overgrowth of some cells in the population, and genetic variation of in vitro cultured cells may result in inaccurate and unreliable prospective information regarding therapeutic treatments. Physicians need a reliable method of obtaining prospective information to assist in personalizing the therapy based on a patient's in vitro tumor behavior.